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某化学科技小组在实验室中对一烧杯浑浊的河水进行了简单净化。 请完成操作中的有关问题： （1）先向烧杯中加入适量明矾粉末，这是利用明矾溶于水后生成的胶状物对杂质的________，使杂质________来达到净水的目的。 （2）再进行过滤液体： ①过滤操作所必需的仪器：________。 A．烧杯B．酒精灯C．铁架台（带）D．试管E．玻璃棒F．漏斗G．托盘天平H．蒸发皿 ②玻璃棒的作用是________________________________，玻璃棒下端接触的部分是________层滤纸处。 ③若滤液仍然浑浊，你认为其原因可能是________________________________。 （3）再用活性炭除去水中的异味，这是利用了活性炭的________作用。 （4）最后进行蒸馏： ①蒸馏时加入沸石的目的是________________________；加热烧瓶，注意不要使液体沸腾得太剧烈，以防________________________________________。 ②所得蒸馏水是_____（填“硬水”或“软水”），检验的简单方法是_________________________。
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【简答题】Complete the sentences with words or the expression from Exercise A. 1. The _______________, which is the largest bedroom in a house or an apartment, usually has its own bathroom. 2. We have a nice___...
【简答题】Complete the sentences with words or the expression from what you've learned. 1. The _________ ______, which is the largest bedroom in a house or an apartment, usually has its own bathroom. 2. We have...
【单选题】选出与本句意思一致的选项 Learning humanities was secure repetition in China, but it was shaky originality here. (Para.5)
A.
If one learned humanities in China, one felt safe because it was all about repeating what had been taught. However, if one learned humanities here in the U.S., one would be shaking all over because he/she had to come up with his/her own ideas.
B.
If one learned humanities in China, one just repeated the correct answers given by the teacher and there was no uncertainty at all. However, if one learned humanities here, one had to come up with his/her own ideas, which made one feel insecure and nervous.
【简答题】仓库安全生产中,对人力操作基本要求是人力作业仅限制在轻负荷的作业。( )
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